const root = typeof window === 'object' ? window : {};
const HEX_CHARS = '0123456789abcdef'.split('');
const EXTRA = [-2147483648, 8388608, 32768, 128];
const SHIFT = [24, 16, 8, 0];
const OUTPUT_TYPES = ['hex', 'array', 'digest', 'arrayBuffer'];

let blocks = [];

const createOutputMethod = (outputType) => {
    return (message) => {
        return new Sha1(true).update(message)[outputType]();
    };
};
const createMethod = () => {
    let method = createOutputMethod('hex');
    method.create = () => new Sha1();
    method.update = (message) => method.create().update(message);
    for (let i = 0; i < OUTPUT_TYPES.length; i++) {
        const type = OUTPUT_TYPES[i];
        method[type] = createOutputMethod(type);
    }
    return method;
};

const Sha1 = function (sharedMemory) {
    if (sharedMemory) {
        blocks[0] = blocks[16] = blocks[1] = blocks[2] = blocks[3] =
            blocks[4] = blocks[5] = blocks[6] = blocks[7] =
            blocks[8] = blocks[9] = blocks[10] = blocks[11] =
            blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0;
        this.blocks = blocks;
    } else {
        this.blocks = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
    }
    this.h0 = 0x67452301;
    this.h1 = 0xEFCDAB89;
    this.h2 = 0x98BADCFE;
    this.h3 = 0x10325476;
    this.h4 = 0xC3D2E1F0;

    this.block = this.start = this.bytes = this.hBytes = 0;
    this.finalized = this.hashed = false;
    this.first = true;
};

Sha1.prototype.update = function (message) {
    if (this.finalized) {
        return;
    }
    const notString = typeof (message) !== 'string';
    if (notString && message.constructor === root.ArrayBuffer) {
        message = new Uint8Array(message);
    }
    let code, index = 0,
        i, length = message.length || 0,
        blocks = this.blocks;

    while (index < length) {
        if (this.hashed) {
            this.hashed = false;
            blocks[0] = this.block;
            blocks[16] = blocks[1] = blocks[2] = blocks[3] =
                blocks[4] = blocks[5] = blocks[6] = blocks[7] =
                blocks[8] = blocks[9] = blocks[10] = blocks[11] =
                blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0;
        }

        if (notString) {
            for (i = this.start; index < length && i < 64; ++index) {
                blocks[i >> 2] |= message[index] << SHIFT[i++ & 3];
            }
        } else {
            for (i = this.start; index < length && i < 64; ++index) {
                code = message.charCodeAt(index);
                if (code < 0x80) {
                    blocks[i >> 2] |= code << SHIFT[i++ & 3];
                } else if (code < 0x800) {
                    blocks[i >> 2] |= (0xc0 | (code >> 6)) << SHIFT[i++ & 3];
                    blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3];
                } else if (code < 0xd800 || code >= 0xe000) {
                    blocks[i >> 2] |= (0xe0 | (code >> 12)) << SHIFT[i++ & 3];
                    blocks[i >> 2] |= (0x80 | ((code >> 6) & 0x3f)) << SHIFT[i++ & 3];
                    blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3];
                } else {
                    code = 0x10000 + (((code & 0x3ff) << 10) | (message.charCodeAt(++index) &
                        0x3ff));
                    blocks[i >> 2] |= (0xf0 | (code >> 18)) << SHIFT[i++ & 3];
                    blocks[i >> 2] |= (0x80 | ((code >> 12) & 0x3f)) << SHIFT[i++ & 3];
                    blocks[i >> 2] |= (0x80 | ((code >> 6) & 0x3f)) << SHIFT[i++ & 3];
                    blocks[i >> 2] |= (0x80 | (code & 0x3f)) << SHIFT[i++ & 3];
                }
            }
        }

        this.lastByteIndex = i;
        this.bytes += i - this.start;
        if (i >= 64) {
            this.block = blocks[16];
            this.start = i - 64;
            this.hash();
            this.hashed = true;
        } else {
            this.start = i;
        }
    }
    if (this.bytes > 4294967295) {
        this.hBytes += this.bytes / 4294967296 << 0;
        this.bytes = this.bytes % 4294967296;
    }
    return this;
};

Sha1.prototype.finalize = function () {
    if (this.finalized) {
        return;
    }
    this.finalized = true;
    let blocks = this.blocks,
        i = this.lastByteIndex;
    blocks[16] = this.block;
    blocks[i >> 2] |= EXTRA[i & 3];
    this.block = blocks[16];
    if (i >= 56) {
        if (!this.hashed) {
            this.hash();
        }
        blocks[0] = this.block;
        blocks[16] = blocks[1] = blocks[2] = blocks[3] =
            blocks[4] = blocks[5] = blocks[6] = blocks[7] =
            blocks[8] = blocks[9] = blocks[10] = blocks[11] =
            blocks[12] = blocks[13] = blocks[14] = blocks[15] = 0;
    }
    blocks[14] = this.hBytes << 3 | this.bytes >>> 29;
    blocks[15] = this.bytes << 3;
    this.hash();
};

Sha1.prototype.hash = function () {
    var a = this.h0,
        b = this.h1,
        c = this.h2,
        d = this.h3,
        e = this.h4;
    var f, j, t, blocks = this.blocks;

    for (j = 16; j < 80; ++j) {
        t = blocks[j - 3] ^ blocks[j - 8] ^ blocks[j - 14] ^ blocks[j - 16];
        blocks[j] = (t << 1) | (t >>> 31);
    }

    for (j = 0; j < 20; j += 5) {
        f = (b & c) | ((~b) & d);
        t = (a << 5) | (a >>> 27);
        e = t + f + e + 1518500249 + blocks[j] << 0;
        b = (b << 30) | (b >>> 2);

        f = (a & b) | ((~a) & c);
        t = (e << 5) | (e >>> 27);
        d = t + f + d + 1518500249 + blocks[j + 1] << 0;
        a = (a << 30) | (a >>> 2);

        f = (e & a) | ((~e) & b);
        t = (d << 5) | (d >>> 27);
        c = t + f + c + 1518500249 + blocks[j + 2] << 0;
        e = (e << 30) | (e >>> 2);

        f = (d & e) | ((~d) & a);
        t = (c << 5) | (c >>> 27);
        b = t + f + b + 1518500249 + blocks[j + 3] << 0;
        d = (d << 30) | (d >>> 2);

        f = (c & d) | ((~c) & e);
        t = (b << 5) | (b >>> 27);
        a = t + f + a + 1518500249 + blocks[j + 4] << 0;
        c = (c << 30) | (c >>> 2);
    }

    for (; j < 40; j += 5) {
        f = b ^ c ^ d;
        t = (a << 5) | (a >>> 27);
        e = t + f + e + 1859775393 + blocks[j] << 0;
        b = (b << 30) | (b >>> 2);

        f = a ^ b ^ c;
        t = (e << 5) | (e >>> 27);
        d = t + f + d + 1859775393 + blocks[j + 1] << 0;
        a = (a << 30) | (a >>> 2);

        f = e ^ a ^ b;
        t = (d << 5) | (d >>> 27);
        c = t + f + c + 1859775393 + blocks[j + 2] << 0;
        e = (e << 30) | (e >>> 2);

        f = d ^ e ^ a;
        t = (c << 5) | (c >>> 27);
        b = t + f + b + 1859775393 + blocks[j + 3] << 0;
        d = (d << 30) | (d >>> 2);

        f = c ^ d ^ e;
        t = (b << 5) | (b >>> 27);
        a = t + f + a + 1859775393 + blocks[j + 4] << 0;
        c = (c << 30) | (c >>> 2);
    }

    for (; j < 60; j += 5) {
        f = (b & c) | (b & d) | (c & d);
        t = (a << 5) | (a >>> 27);
        e = t + f + e - 1894007588 + blocks[j] << 0;
        b = (b << 30) | (b >>> 2);

        f = (a & b) | (a & c) | (b & c);
        t = (e << 5) | (e >>> 27);
        d = t + f + d - 1894007588 + blocks[j + 1] << 0;
        a = (a << 30) | (a >>> 2);

        f = (e & a) | (e & b) | (a & b);
        t = (d << 5) | (d >>> 27);
        c = t + f + c - 1894007588 + blocks[j + 2] << 0;
        e = (e << 30) | (e >>> 2);

        f = (d & e) | (d & a) | (e & a);
        t = (c << 5) | (c >>> 27);
        b = t + f + b - 1894007588 + blocks[j + 3] << 0;
        d = (d << 30) | (d >>> 2);

        f = (c & d) | (c & e) | (d & e);
        t = (b << 5) | (b >>> 27);
        a = t + f + a - 1894007588 + blocks[j + 4] << 0;
        c = (c << 30) | (c >>> 2);
    }

    for (; j < 80; j += 5) {
        f = b ^ c ^ d;
        t = (a << 5) | (a >>> 27);
        e = t + f + e - 899497514 + blocks[j] << 0;
        b = (b << 30) | (b >>> 2);

        f = a ^ b ^ c;
        t = (e << 5) | (e >>> 27);
        d = t + f + d - 899497514 + blocks[j + 1] << 0;
        a = (a << 30) | (a >>> 2);

        f = e ^ a ^ b;
        t = (d << 5) | (d >>> 27);
        c = t + f + c - 899497514 + blocks[j + 2] << 0;
        e = (e << 30) | (e >>> 2);

        f = d ^ e ^ a;
        t = (c << 5) | (c >>> 27);
        b = t + f + b - 899497514 + blocks[j + 3] << 0;
        d = (d << 30) | (d >>> 2);

        f = c ^ d ^ e;
        t = (b << 5) | (b >>> 27);
        a = t + f + a - 899497514 + blocks[j + 4] << 0;
        c = (c << 30) | (c >>> 2);
    }

    this.h0 = this.h0 + a << 0;
    this.h1 = this.h1 + b << 0;
    this.h2 = this.h2 + c << 0;
    this.h3 = this.h3 + d << 0;
    this.h4 = this.h4 + e << 0;
};
Sha1.prototype.hex = function () {
    this.finalize();

    let h0 = this.h0,
        h1 = this.h1,
        h2 = this.h2,
        h3 = this.h3,
        h4 = this.h4;

    return HEX_CHARS[(h0 >> 28) & 0x0F] + HEX_CHARS[(h0 >> 24) & 0x0F] +
        HEX_CHARS[(h0 >> 20) & 0x0F] + HEX_CHARS[(h0 >> 16) & 0x0F] +
        HEX_CHARS[(h0 >> 12) & 0x0F] + HEX_CHARS[(h0 >> 8) & 0x0F] +
        HEX_CHARS[(h0 >> 4) & 0x0F] + HEX_CHARS[h0 & 0x0F] +
        HEX_CHARS[(h1 >> 28) & 0x0F] + HEX_CHARS[(h1 >> 24) & 0x0F] +
        HEX_CHARS[(h1 >> 20) & 0x0F] + HEX_CHARS[(h1 >> 16) & 0x0F] +
        HEX_CHARS[(h1 >> 12) & 0x0F] + HEX_CHARS[(h1 >> 8) & 0x0F] +
        HEX_CHARS[(h1 >> 4) & 0x0F] + HEX_CHARS[h1 & 0x0F] +
        HEX_CHARS[(h2 >> 28) & 0x0F] + HEX_CHARS[(h2 >> 24) & 0x0F] +
        HEX_CHARS[(h2 >> 20) & 0x0F] + HEX_CHARS[(h2 >> 16) & 0x0F] +
        HEX_CHARS[(h2 >> 12) & 0x0F] + HEX_CHARS[(h2 >> 8) & 0x0F] +
        HEX_CHARS[(h2 >> 4) & 0x0F] + HEX_CHARS[h2 & 0x0F] +
        HEX_CHARS[(h3 >> 28) & 0x0F] + HEX_CHARS[(h3 >> 24) & 0x0F] +
        HEX_CHARS[(h3 >> 20) & 0x0F] + HEX_CHARS[(h3 >> 16) & 0x0F] +
        HEX_CHARS[(h3 >> 12) & 0x0F] + HEX_CHARS[(h3 >> 8) & 0x0F] +
        HEX_CHARS[(h3 >> 4) & 0x0F] + HEX_CHARS[h3 & 0x0F] +
        HEX_CHARS[(h4 >> 28) & 0x0F] + HEX_CHARS[(h4 >> 24) & 0x0F] +
        HEX_CHARS[(h4 >> 20) & 0x0F] + HEX_CHARS[(h4 >> 16) & 0x0F] +
        HEX_CHARS[(h4 >> 12) & 0x0F] + HEX_CHARS[(h4 >> 8) & 0x0F] +
        HEX_CHARS[(h4 >> 4) & 0x0F] + HEX_CHARS[h4 & 0x0F];
};

Sha1.prototype.toString = Sha1.prototype.hex;

Sha1.prototype.digest = function () {
    this.finalize();

    let h0 = this.h0,
        h1 = this.h1,
        h2 = this.h2,
        h3 = this.h3,
        h4 = this.h4;

    return [
        (h0 >> 24) & 0xFF, (h0 >> 16) & 0xFF, (h0 >> 8) & 0xFF, h0 & 0xFF,
        (h1 >> 24) & 0xFF, (h1 >> 16) & 0xFF, (h1 >> 8) & 0xFF, h1 & 0xFF,
        (h2 >> 24) & 0xFF, (h2 >> 16) & 0xFF, (h2 >> 8) & 0xFF, h2 & 0xFF,
        (h3 >> 24) & 0xFF, (h3 >> 16) & 0xFF, (h3 >> 8) & 0xFF, h3 & 0xFF,
        (h4 >> 24) & 0xFF, (h4 >> 16) & 0xFF, (h4 >> 8) & 0xFF, h4 & 0xFF
    ];
};

Sha1.prototype.array = Sha1.prototype.digest;

Sha1.prototype.arrayBuffer = function () {
    this.finalize();

    const buffer = new ArrayBuffer(20);
    let dataView = new DataView(buffer);
    dataView.setUint32(0, this.h0);
    dataView.setUint32(4, this.h1);
    dataView.setUint32(8, this.h2);
    dataView.setUint32(12, this.h3);
    dataView.setUint32(16, this.h4);
    return buffer;
};

export default createMethod();
